Actually, a recent study from the University of Florida showed that knee pain is a very small part of the problem. The real issue is a loss of muscle activation and strength. The quadriceps muscle along the front of the thigh seems to be affected the most.
You may do best with a program of physical therapy to improve muscle activation. High-intensity muscle contractions is the first place to start. Biofeedback and electrical stimulation may help too.
Check with your doctor first about pain control. After four months your pain level should be more manageable. Then ask about a follow-up rehab program to address the problem of muscle atrophy and weakness.